The Synthetic and Analytical Core Project forms the underpinning for all research projects in the Program by furnishing modified oligodeoxynucleotides and analytical services for all investigators. The objectives of the Core are (a) to synthesize modified deoxynucleosides that represent endogenous DNA damage and to convert them to the 5'-O-DMT-3'-O-phosphoramidites for incorporation into oligodeoxynucleotides; (b) to generate highly pure, site-specifically modified oligodeoxynucleotides using automated DNA synthesis techniques; and (c) to provide essential analytical services, including mass spectrometry, HPLC, and capillary electrophoresis, for all participants in the program. In addition, the Core Facility will develop new synthetic methods and analytical techniques needed for Program research and for the operation of a state-of-the-art facility. Combining the synthetic and analytical aspects of Program research in a Core facility operated with highly trained personnel will guarantee timely access to modified oligodeoxynucleotides for all Program participants and ensure that major equipment items are available and functioning.